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* [PATCH] Fix SSBD not being exposed to guests. (v1)
@ 2018-05-21 21:54 Konrad Rzeszutek Wilk
  2018-05-21 21:54 ` [PATCH] KVM: VMX: Expose SSBD properly to guests Konrad Rzeszutek Wilk
  0 siblings, 1 reply; 5+ messages in thread
From: Konrad Rzeszutek Wilk @ 2018-05-21 21:54 UTC (permalink / raw)
  To: x86, kvm, linux-kernel

Hi,

Without this patch, when launching QEMU with -cpu +ssbd I ended up
with a warning seeing that the CPU does not support - which in fact it does.

The issue was the X86_FEATURE_ -  the kvm_cpuid_7_0_edx_x86_features
had bit 17 set (X86_FEATURE_SSBD), while the right bit should have been
bit 31 ( X86_FEATURE_SPEC_CTRL_SSBD). That meant the masking:

	entry->edx &= kvm_cpuid_7_0_edx_x86_features;

would nicely clear the SSBD bit.

This fixes:
Fixes: 52817587e706 ("x86/cpufeatures: Disentangle SSBD enumeration")

 arch/x86/kvm/cpuid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Konrad Rzeszutek Wilk (1):
      KVM: VMX: Expose SSBD properly to guests.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2018-06-07 13:25 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-21 21:54 [PATCH] Fix SSBD not being exposed to guests. (v1) Konrad Rzeszutek Wilk
2018-05-21 21:54 ` [PATCH] KVM: VMX: Expose SSBD properly to guests Konrad Rzeszutek Wilk
2018-05-22 23:50   ` Ben Hutchings
2018-06-07 13:14     ` Thomas Voegtle
2018-05-23  9:00   ` [tip:x86/pti] KVM/VMX: " tip-bot for Konrad Rzeszutek Wilk

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